The review by Gonner [1]} shows that the equations of the Kaluza scalar field were developed by multiple European research groups in the mid-20th century, but none of those results were published in English language journals. The war caused further disruptions in the dissemination of results obtained by the European groups. The English-language Kaluza literature of the late 20th century (see Ref. [2]} for a review) contains variations in the field equations, and various authors make differing assumptions regarding the form of the Kaluza Lagrangian. The correct form of the Kaluza Lagrangian was obtained by Refs. [3]} and [4]}, and their result was verified using tensor algebra software [5]}. Ref. [4]} also obtains the correct curvature tensors, while Ref. [3]} has some minor errors in the 5D Ricci tensors.[5]}
